Submission #671575

#	Time	Username	Problem	Language	Result	Execution time	Memory
671575		viwlesxq	Divide and conquer (IZhO14_divide)	C++17	0 / 100	1 ms	212 KiB

divide

#include <bits/stdc++.h>
//#include "ext/pb_ds/assoc_container.hpp"
//#include "ext/pb_ds/tree_policy.hpp"

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
typedef string str;

#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
//#define ordered_set tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update>
//void freo(str x) {freopen((x + ".in").c_str(), "r", stdin);freopen((x + ".out").c_str(), "w", stdout);}
 
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin >> n;
	ll x[n], g[n], d[n];
	for (int i = 0; i < n; i++) cin >> x[i] >> g[i] >> d[i];
	ll ans = *max_element(g, g + n);
	vector <ll> pref_d(n), pref_g(n), suff_max(n);
	pref_d[0] = d[0];
	pref_g[0] = g[0];
	for (int i = 1; i < n; i++) {
		pref_d[i] = pref_d[i - 1] + d[i];
		pref_g[i] = pref_g[i - 1] + g[i];
	}
	suff_max[n - 1] = pref_d[n - 1] - x[n - 1];
	for (int i = n - 2; i >= 0; i--) {
		suff_max[i] = max(suff_max[i + 1], pref_g[i] - x[i]);
	}
	for (int i = 0; i < n; i++) {
		int l = i, r = n;
		while (l + 1 < r) {
			int mid = (l + r) / 2;
			ll add = -x[i];
			if (i) add += pref_d[i - 1];
			if (suff_max[mid] >= add) l = mid;
			else r = mid;
		} 
		if (i) ans = max(ans, pref_g[l] - pref_g[i - 1]);
		else ans = max(ans, pref_g[l]);
	}
	cout << ans;
}

• Subtask 1: 0 / 17
• Subtask 2: 0 / 31
• Subtask 3: 0 / 52